This has not been done on its own as a thread but has been mentioned in countless others.
If Labour win in 1992, the first immediate difference to an OTL observer would be that you have Tony Blair battling Gordon Brown - but in the guise of Neil Kinnock and John Smith. Two egos fighting over the economy which was already bruised over the shock of 1987 and 11 years of Margaret Thatcher. The Labour party shadow budget would give you some fairly good pointers as to how the Kinnock administration would have operated.
Rich to be heavily taxed, the poor not quite so heavily taxed was the first part of the budget but the Tories spun this into a campaign saying the average family would be at least a thousand pounds worse off under Labour, which was as close to an outright lie as one could get but the public swallowed it. A 10% tax increase on the upper band earners would hit the South East hard but as they weren't voting Labour, it would have hardly mattered to Neil Kinnock.
The main thrust of the 1992 campaign was the overall redistribution of wealth to even out the inequalities in British society, particularly those hit by the recession. Social spending would have seen an increase at the expense at the tax rises for higher earners. Labour might have been tempted to, as an earlier poster indicated, hit some of the right wing institutions such as the media who'd been actively hostile.
The problem that a 1992 Labour Government would have had would have been that the "loony-left" hadn't gone away as they all but had in 1997. Indeed in the book "President Gore", this particular scenario was explored and Kinnock has problems from the usual left-wing firebrands in the party like Alan Simpson.
Black Wednesday would have still hit the British economy but it's difficult to tell how deep the effects would have run. With more money in Government hands through increased taxation, there would have been more cash in the hands of the Treasury which would have some sort of impact. If the UK similarly leaves the ERM, Sterling would be allowed to float to its natural value rather than be tied to the Deutschmark and the economy could recover.
I'd have to check the book to see what else Labour did/does during its fictional tenure but I have a feeling it wins in 1997 for some reason.
What is easier to offer speculations on is the Conservative Party in 1992. Two scenarios will arise - either it'll destroy itself through infighting and a growing ideological rift between pro and anti Europeans or it'll get a new Leader and coelesce around him her. In 1992 the major candidates would be Ken Clarke, Malcolm Rifkind, Michael Howard and Michael Heseltine. Ken Clarke hasn't been Chancellor yet although he's not done badly at Education so a senior job would be in the offing. Michael Howard hasn't been tainted by the Home Office but is still responsible for the Poll Tax. Heseltine is still seen as Thatcher's assassin so Rifkind, assuming there isn't an outsider, would probably win the Leadership, almost by default. He's a moderate and not seen as tainted goods.
Of course, the various factions inside the party could take a loss in 1992 to trigger a virtual civil war in the Conservatives making it a hideous mess for the next decade as each group tries to blame each other for the colossal failures of the Thatcher administration.